Alternative peep sights to fit Henry?

I had my Henry H001Y out shooting yesterday. It has the stock sights on it. I was shooting at 25 yards - plain round nose Federal LR (I picked up a brick of them last week to try - really liked the way they shot).

O.K. I'm 60, have to shoot left handed due to eye problems. I've been using a piece of white paper 4 X 6 with a felt pen X corner to corner and a tracing of a quarter in the center of the X. This gives a good contrast for me for the sights. After putting 50 rounds through - I had several dead center and most of the rest about at 7 o'clock maybe an inch away. I don't' attribute this to my sights being off as I discovered that as I'm getting used to shooting the lever gun left handed, I had developed a couple of bad habits. One, when I squeezed the trigger, I could tell that I was "twisting" the rifle just a little bit. I wasn't flinching - it was all in how I was squeezing the trigger. Tjhis lead to me discovering that I did not have the stock firmly seated against my shoulder. I seemed to be ablet to help this by moving my right hand on the fore stock so that my right thumb and under finger were in front of the barrel band and thus I could "pull" it back into my shoulder for a tighter fit/grip.

Now . . . while the stock sights are "so so", I find that i am having trouble concentrating on the front sight and getting it "centered" in the rear sight slot. I'd like to try a peep sight as I think that might be the answer for me. I"ve looked at the Skinner sights and yes they are very nice. However, adding them to my rifle would make it necessary to replace the front "plastic" band/sight. All of these changes add up to $$.

My question is this. Does anyone make a peep sight that will fit the receiver mounting grooves like the skinner does but which is cheaper? I like the H001Y but at some point am going to get the Frontier and on that one, I'd put the extra $$ into a Skinner sight. I'm not interested in the expense of a tang peep. I'd like something that wouldn't require drilling/tapping holes and realize that the front sight would have to be changed anyway.This is just a "knock about" plinking rifle and I'd like to get out of it for the least amount of money. I know "you get what you pay for" but I'd rather put better upgrades into a Frontier when I get it but still want to try a peep and see if it will answer my vision requirements. Does such an animal exist?

Thanks.