MAIN TARGA SEAL
Do the sides first then the top starting at the center. The clip is tight, so if you need to you can open up about a 2“ section of the top seal by pushing in a screwdriver (flat). Do not twist. This will allow for you to start the seal. Using warm soapy water will help also.
It is possible the clip is not fully engaged as it is tight. We made it this way as the complaint was it would come off with the top if the top had been on for awhile. Soapy water or glycerine work well to help persuade it all the way on. You can use a large flat screwdriver to open up about 3” in the center of the top. This will allow for you to see it fully engaged and help it to slide on. I prefer to install the sides first, then the top from the center so it's not stretched one direction too far leaving too much material on one end.
It is normal for it to be difficult to engage. If the seal isn't sitting on the front edge, it's not fully engaged. Pop it back off as it's not all the way on (only the top section). open up the center 3“ or so with a flat screwdriver so you can start the seal. Lubricate the seam it sits on with soapy water. Then take a wood block and a rubber mallet to tap the seal on. If you have second set of hands to grip the seal pulling it in while you tap on the block you should find it can be persuaded into place.
BE CAREFUL when removing the seal, and when installing that the metal clip is not pulled out of the metal and it is not binding as you are trying to install. The latter is a matter of it not going squarely into the channel. It can be corrected, but why create more work if you are aware of a potential install pitfall.
About the adhesive: the main Targa seal has the metal clip that needs to go over the pinch welded lip. The problem is that if it's not tight it will pop off. The technique is to open up the center 2-3” using a flat screw driver. This allows it to start onto the lip. The weather-strip adhesive is if the metal is a little lose to hold it on. You should be able to install using soapy water to allow for lubrication (glycerin also works). It is imperative that when you install it you do not pull it as it will stretch the seal leaving you more material that can fit.. This will require removal and re-installation and once the clip has been widened it may be more prone to come off with the roof requiring the adhesive. If adhesive is required you can put a few 1“ beads just on the top of the welded seam. I use recommend the 3M weatherstrip adhesive as it will stay somewhat tacky and is easier to clean up.
Note: Targa roof to window seal - Many people try to pull the seals on the roof at the top of the window. Yes they can be pulled through the track, and you think that you have relieved all the tension, but in a month or more, the vibration / expansion and contraction will eventually allow the runner to return to the un-stretched shape. Rubber has memory, and will do this, so even a small amount of stress will eventually cause this seal to mysteriously shrink. The only way to avoid this is to install the outside edge 1st and them press in the inner edge. We make the seal about 1/4” longer than you think you will need. Install the roof and try to close the front latch. You will notice the seal will “beer can”or crumple in. Take a carpet knife and warm soapy water and shave off up to 1/8“ and re try. Continue the process until you can see that seal is actually making contact and is under pressure, but not so much that it deforms the seal. This will allow for the best possible fit.