How about this method... it is working for me!
1) Click on "Thread Start Date" ... now the newest contests will be listed from newest to oldest down the page
2) Scroll down (however many pages) to where you see your last blue arrow (on the far left)
3) Click on the next contest above the one with the blue arrow. Do your usual: checking the thanks button, entering the contest. BUT.... instead of entering a reply (thx, thanks, entered, good luck)... go to Step 4
4) Click on your browser's back button.
5) Click on the 2nd next contest above the one with the blue arrow. Repeat Step 3 stuff and then Step 4.
6) Keep repeating Steps 3 to 5
7) When you are either tired of contesting or have reached the last available contest to enter... write in your thx, thanks on that one thread.... This will create a blue arrow on your last contest of the session.
8) Next time you arrive... repeat Steps 1 to 7
Sounds wordy, but I'm describing it as best I can.
What you'll end up with is only one thanks/thx/good luck posting (better than having to reply to every thread). You also won't need to memorize where you last left off yesterday or last week.
Is this a reasonable compromise between the thanks but no thanks factions?