You can glean much of the information you require from those who have visited previously & included details accompanying their photo-postings. 4-Aviation Tours to these locations also have detail reports on previous Tours which give an indication of bases which provide better opportunities than others. Google Taiwan weather seasons & see if your conclusions match others actual experience as preferable times to visit. Your main issues revolve around security & the anti-Communist China threat, which Europeans visiting Taiwan can incredibly be included in.
Most all bases (except Training bases?) are surrounded by high concrete walls which preclude any view into the base. If you can find an elevated viewing location, the chances of remaining there for long can be as little as twenty minutes. Even the 'Locals' don't show themselves until the last minute to get their shots. You will certainly come under surveillance from minute 5 of arrival. Typically pseudo-spotters with small SLR cameras whose preference is to immediately pretend to use their mobile phone by putting to their ear to take pictures of you, whilst paying no attention to the flying in front of them!
Frequent interviews by 'Men in Black' or airbase Military Security personnel, or both is usual & thereafter your presence is reluctantly tolerated, provided you don't photograph into the base!(even though the Locals do?) Worse by far are the Civil Police who have ZERO understanding & tolerance! They will remove you immediately from whatever location you choose, including the public highway & robustly deny your return.

There is definitely an air of adventure to visiting Taiwan, but the low-risk stalking of images can be well worth it! Good Hunting.