I look'd, but did not find the thread showing the HT1 guts. You should disconnect the power cord and work on the amp with it laying flat and speaker downwards. I loosened the back screws and removed them. The rear handle screws, I just sufficiently loosen several screwdriver turns without removing them. Gently pry up one corner of the back plate and with both hands gently inch out the works. Mine fit quite snug, as it should. Reach in and loosen the speaker leads gradually. Remove each and continue lifting the works out and set aside. I did all of this with the amp laying flat; speaker grill down. Reverse the procedure when re-inserting the works. Tighten the handle screws, put the back in place and put just 4 corner screws back and test the amp before putting the remaining back screws in place.
With the original speaker in, the amp does have a preponderance of "bass" due to the closed-back design. You can tweak the amp controls to lessen this effect. On the clean channel, have the volume maxed. Put the gain somewhere around 10:00 o'clock, and the ISF the same, perhaps a shade less. With my Les Paul humbuckers I get a workable clean tone and control the volume with the guitar. These settings depend on the area you are playing in, so experiment with those settings. The Celestion lessens the bass somewhat, but it' s quite enough
for my needs. You can control some of the bass by experimenting with the amp's controls. I like a lot of bass for a "full" broad sound, especially when practicing alone.
The finger noise is mostly likely you, and not the amp. I don't get finger noise on my electrics, but sometimes on acoustic. Over time you mind find that you develop fingering techniques subconsciously that get rid of most of it.....I did.